Now guess what? The QA team rewrites it in python. They have a very little knowledge of python so their code looks like spagetti,
and even worse - they cant cover the needed functionality because of lack of python competency, but they forced to do it
because of everyone, starting from the management, is scared of perl. They don't even want to give it a try!

I suspect the QA team not only lack Python competency, but lack general software development competency,
a common problem with QA teams in my experience.

Still, I sympathize with their overall approach.
After all, the QA team are responsible for maintaining this code, not you.
And what happens if you leave the company?
Has your company made their policy of which programming
languages you may use clear? If they have mandated Python,
how come you are allowed to write a system in Perl?
And if they have not mandated a single scripting language,
they are asking for trouble IMHO, with you writing a
system in Perl, others choosing Python, others preferring
Ruby, others opting for Lua, or Power Shell, or Groovy, or ...

You see, when you commit to maintaining large systems
over a period of many years, by many different programmers,
it is not economic for a company to maintain
a high level of competency across many different languages
because mastering, as opposed to dabbling in, a language, and its libraries,
and its community, takes a lot of time and effort.
Even a company as big as Google for many years allowed only three languages
to be used for production code, namely C++, Java and Python.

Please tell me I'm just a deviation and you have changed
employer recently and still working in perl tolerating company.

I am happy to report that I work in a Perl tolerating company.
Every now and then, some keen new starter wants to drop Perl
and switch to Python or Ruby. If you propose that, however, what
is your plan to deal with the millions of lines of critical
functionality already implemented in Perl?
What is the return on investment in rewriting a working system
in another language? What is the benefit to the customer?
And if you don't rewrite, you must commit to maintaining
skills across multiple languages for many years, a step
not to be undertaken lightly.

You're right on all your statements and most of your assumptions, but please take into account the following:

there was no automated testings before I came here. QA guys did all testings manually, slowly, step by step as written on their wikis, by hand.

there was no standard for automated tests and no preferences for auxiliary scripting tools.

considering the python knowledge. At this point there is me and one more guy from support with perl knowledge against one developer and one team lead with stated python backgound.

I did provide the test suite as a helper tool to speed up the testing process. Those guys from QA was excited about it but then this management came with their decision to rewrite the whole test suite.